The idea behind smoothing wood has had effects on both the visual appearance of an object as well as its texture and feel since man first used tools. The feel of tools and instruments and the way they perform has has long been effected  by methods of smoothing them. The sand hasn’t always been just on the paper. Historically wood has been smoothed by rubbing wood on stone or rubbing a stone on wood.
Millions of years ago, when I was a kid, we felt, like all other kids, the need for spears. Since wise and discerning adults had hid all the sharp tools, we were only left with the obvious method of sharpening sticks.  Another historical method of sanding was drawing a sharp edge perpendicularly to the surface being smoothed. On rare occasions, I will still grab a piece of broken glass and draw it along an uneven surface, to remove material faster, in a hard to reach location. Since the historicity of arrow and spear heads makes them off limits, and a cabinet scraper won’t fit in some places, sometimes even using a utility knife blade will work wonders. But… most of the time sandpaper is the answer. Not wanting to count, I’m sure that we have a least 30 different power tools that use abrasive paper or cloth. If you want it smooth and clean, sandpaper is your friend.